Skip to Main Content
Book Chapter

Faulting and forced folding in the Rocky Mountains foreland

David W. Stearns
David W. Stearns
Search for other works by this author on:
January 01, 1978

The structural basement in the Rocky Mountains foreland deforms by faulting and rigid-body rotations. The faults at the interface between the sedimentary and crystalline rocks can be anything from low-angle reverse to normal faults. Despite the range of geometries, the total assemblage of faults and rotations is best explained by a movement system that is dominated by vertical motions along faults, many of which are curved in cross section. The first causes deep within the crust are not sufficiently well documented in the geophysical record to justify a firm interpretation. However, there are certain conditions recorded in the geologic history of the region and in the surface structures that place constraints even on speculations. With these constraints, vertical movements seem more likely to dominate than horizontal movements. The sedimentary layers are deformed primarily by forced folding. Their final geometry is a product of several parameters such as welding and stratigraphic make-up. Measurements on natural folds demand that the section either thinned or detached. Detachment without appreciable thinning further requires that (1) large displacements occur within the sedimentary section and (2) at the termination of these folds, the movement must be in several directions. Geologists’ intuition as to how the layered rocks achieved their shapes is not always correct, but field data combined with experimental and theoretical data provide a basis for understanding these folds. It is concluded that the structural style in the Rocky Mountains foreland is not unique, but rather it is only an excellent example of a more universal class of deformation, namely, forced folding.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables


GSA Memoirs

Laramide Folding Associated with Basement Block Faulting in the Western United States

Vincent Matthews, III
Vincent Matthews, III
Search for other works by this author on:
Geological Society of America
ISBN print:
Publication date:
January 01, 1978




A comprehensive resource of eBooks for researchers in the Earth Sciences

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now